The present invention relates to a testing device for testing functional units, such as an exposing unit, a developing unit, a transferring unit, a fixing unit, and a paper feeding system of an electrophotographic imaging apparatus.
Conventionally, there has been known an imaging apparatus employing a so-called electrophotographic imaging method, such as an electronic copy machine and a laser beam printer, etc. In such an electrophotographic imaging apparatus, an exposure operation is performed by an exposing unit in such a manner that a uniformly charged surface of a photoconductive drum is exposed to light to form a latent image on the basis of Image information. Then, a developing unit attaches toner onto the latent image so as to form a toner image. The toner image is transferred onto a recording paper by a transferring unit. Subsequently, the transferred image is fixed onto a recording sheet by a fixing section.
Generally, an electrophotographic imaging apparatus includes: an engine driver board for receiving data from a host computer, or the like, and for driving each of the functional units, such as, for example, an exposing unit, a developing unit, a transfer unit, a fixing unit, etc.; and a printer controller for supplying data relating to an image to be printed, for example, such as, for example, a video signal, page-size data, etc. to the engine driver board.
In the printing operation of the electrophotographic imaging apparatus, data communication is performed between the printer controller and the engine driver board in such a fashion that the printer controller outputs data relating to an image to be printed in response to the requirement of the engine driver board. Then, the engine driver drives each function unit with reference to data representing an operational condition, such as, for example, a sheet-feed condition, temperature of the fixing unit, etc., of the function units.
In an assembly line of the electrophotographic imaging apparatus, a performance test is required for checking a basic function of each of the function units of the imaging apparatus, such as, a sheet-feed function, temperature control function, and so on. When the performance test is executed, the engine driver and the printer controller are disconnected, and an external testing device is connected to the engine driver board for communicating the engine driver board instead of the printer controller. Then, the testing device performs checking of basic function of the individual imaging apparatus by sending the data relating to an image, which is selected as suitable for testing purposes, to the engine driver board.
As described above, since each functional unit is driven based on the communication between the testing device and the engine driver board, the printer controller in the electrophotographic imaging apparatus is conventionally disconnected from the engine driver board upon connection of the testing device to the engine driver board.
In order to develop a new printer controller or Improving a conventional printer controller, it is preferable that the operational condition of the function units of the imaging apparatus be monitored with the print controller and the engine driver board being connected.
When an actual printing operation is executed without the testing device, that is, the engine driver is connected with the printer controller, since the operational condition of each function unit is transmitted only between the engine driver board and the printer controller, it is difficult to monitor the operational condition of the function units from outside.
Some imaging apparatus are equipped with display devices that are directly connected to the printer controller, so as to display some operational condition of the imaging apparatus. This type of display does, however, display only a limited and predetermined number of operational conditions of the imaging apparatus.
On the other hand, the testing device is capable of displaying sufficient numbers of operational conditions of the function units obtained from the engine driver board. However, since the testing device is used for testing the engine driver board, and the printer controller should be disconnected from the testing device when the engine drive and the testing device are connected, it is difficult to monitor the operational conditions of the function units of the imaging apparatus with use of the testing device when the print controller and the engine driver board is connected.